The present invention relates to an improved water filter, particularly concerning a cone-shaped water filter tank using an improved valve including a plurality of conduits, concealed in the filter tank.
As seen in FIG. 1, many of the known designs of water filter used today are designed with a tank body 1, a coupling conduit 11, a plurality of controlling valves 12, a plurality of conduit fittings 13, a baffle plate 14, a filtering bed layer 15 and a backwash distributing conduit 16. The coupling conduit 11 is usually arranged in the open air and out of the tank 1. Such a water filter tank has the following disadvantages:
(1) Most of the coupling conduits 11 are made of heavy metal so that they need a conduit fitting 13 at any bend. Besides, the conduit 11 requires a plurality of controlling valves 12 for different controlling purposes resulting in high manufacturing cost. Even though a plastic conduit can be substituted for the metal conduit, there remains the inconvenience that the whole plastic conduit assembly needs to be supported by a supporting member.
(2) The conduit 11, the controlling valves 12 and the conduit fittings 13 are disposed in the open air year round so they are easily damaged by weather or other incidental accidents, such as being bumped by a heavy load, causing water leakage. sometimes, it may be dangerous for people working around the tank if the conduit assembly is leaking HCl during the backwashing operation of the filter tank.
(3) Since the tank 1 is of cylindrical shape with a filtering bed 15 which includes a layer of sand and a layer of gravel etc., there may be some trouble in rebuilding the filtering bed, if it is disturbed. If the backwash is turned on suddenly, the water may lift the sand bed bodily above the gravel layer, forming an open space between the sand and grave. The filtering bed 15 then breaks at one or more points causing sand boils and subsequent upsetting of the supporting gravel layers. Cracks along the side walls of the tanks may be caused as the filtering bed is pulled away from the side walls of the tank. (see in FIG. 2).
(4) Since the conduit assembly uses a plurality of controlling valves 12, the potential is very great for human error in operation or in turning on and off the water flow.